A • TRANSITION FROM LAMINAR TO TURBULENT FLOW 



if present, by the large velocity fluctuations induced in the boundary 

 layer flow by the external turbulence. 



If this broad outline of the complex problem of transition is correct, 

 it seems doubtful that the modified Schlichting approach based on the 

 notion of a local transition Reynolds number can be anything more than 

 an empirical engineering approximation. It may well be that its utility 

 decreases as the disturbances are made smaller, if in fact it turns out to 

 have any utility. Certainly there is ample room for further investigation 

 of the transition problem. 



A,28. Cited References. 



1. Dryden, H. L. Air flow in the boundary layer near a plate. NACA Reft. 562, 

 1936. 



2. Schubauer, G. B., and Skramstad, H. K. Laminar-boundary-layer oscillations 

 and transition on a flat plate. NACA Rept. 909, 1948. 



3. Emmons, H. W. J. Aeronaut. Sci. 18, 490 (1951). 



4. Mitchner, M. /. Aeronaut. Sci. 21, 350 (1954). 



5. Schubauer, G. B., and Klebanoff, P. S. NACA Tech. Note 3489, 1955. 



6. Wright, E. A., and Bailey, G. W. /. Aeronaut. Sci. 6, 485 (1939). 



7. Schlichting, H., and Ulrich, A. Jahrbuch deut. Luftfahrtforschung I, 8 (1942). 



8. Liepmann, H. W. Investigations on laminar boundary-layer stability and 

 transition on curved boundaries. NACA Advance Confid. Rept. 3HS0, 1943. Also 

 issued as NACA Wartime Rept. W-107,^ 1943. 



9. Feindt, E. G. Untersuchungen iiber die Abhangigkeit des Umschlages laminar- 

 turbulent von der Oberflachenrauhigkeit und der Druck-verteilung. D. F. L. 

 Inst. Aerodynamik, Braunschweig, Bericht 56/10, 1956. 



10. Liepmann, H. W. Investigation of boundary layer transition on concave walls. 

 NACA Advance Confid. Rept. 4J28, 1945. Also issued as NACA Wartime Rept. 

 W-87, 1945. 



11. Gortler, H. Nachr. Ges. Wiss. Gottingen, Fachgruppen I {N.F.)2, 1 (1940). 

 Transl. NACA Tech. Mem. 1375, 1944. 



12. Liepmann, H., and Fila, G. H. Investigations of effects of surface temperature 

 and single roughness elements on boundary-layer transition. NACA Rept. 890, 

 1947. 



13. Fage, A. The smallest size of a spanwise surface corrugation which affects 

 boundary-layer transition on an aerofoil. Brit. Aeronaut. Research Council Repts. 

 and Mem. 2120, 1943. 



14. Holstein, H. Versuche an einer parallel angestromten ebenen Platte iiber den 

 Rauhigkeitseinfluss auf den Umschlag laminar/turbulent. Zent. Wissensch. 

 Berichtsw. uher Lujtfahrtsch, Berlin, Untersuch. u. Mitt. 3110, 1944. See also AVA 

 Monograph Series, RT1005. 



15. Tani, I., Hama, R., and Mituisi, S. On the permissible roughness in the laminar 

 boundary layer. Rept. Aeronaut. Research Inst. Tokyo 199, 1940. 



16. Schiller, L. Handbuch der Experimentalphysik, Vol. 4, Part 4. Leipzig, 1932. 



17. Dryden, H. L. J. Aeronaut. Sci. 20, 477 (1953). 



18. Tani, I., and Hama, F. R. /. Aeronaut. Sci. 20, 289 (1953). 



19. Stiiper, J. The influence of surface irregularities on transition with various 

 pressure gradients. Dept. Supply Aeronaut. Research Consultative Comm. Rept. 

 A59, Melbourne, 1949. See also Aerodynamics Tech. Mem. 77 and 78, 1949; and 

 Z. Fliigwiss. 4, 30 (1956). 



20. Quick, A. W. Einige Bemerkungen iiber Laminarprofile und iiber das Verhalten 

 der laminaren Grenzschicht unter dem Einfluss von Storkorpern. Lilienthal- 

 Gesellschaft Bericht I4I, Supplement, 1941. 



21. Tani, I., Hama, F. R., and Mituisi, S. On the effect of a single roughness element 



< 70) 



